Tocopherol preparation



Patented May2 3, 1944 Kenneth c. n. Hickman me n. Kalil-t, Rochester, N."!., assignors to Distillation Products,-

- lncqltochester ware , N. 1., a corporation of Dela- Application September as, recast-mi No. sssmo 4 Claims- (Ci. tomes) sodium may be used in conjunction with a suit This invention relates to the recovery or puriiication oi tocopherol and in particular relates to a method whereby loss during recovery or purification treatment is considerably lessened.

Three varieties of tocopherol are known to exist-alpha, beta, and gamma. .Each of these is quite easily oxidized, the oxidation passing through several stages at one ofwhich a quinone is present. Although some authorities claim that the quinone form has the full vitamin E activity of the hydroquinone all recognize that it is readily and irreversibly oxidized to a substanc which has no activity.

During smthetic preparation of tocopherols and during purification of tocopherols from natural sources it is convenient or necessary to extract, distill, esterify, saponify, or use similar pro cedure to eflect a satisfactory separation or purificatiom During such processes, and particularly during saponification or neutralization, any tocopherols which are present will partly become irreversibly oxidizedwith a resulting high loss of the original tocopherol contained in the mixture being treated.

- This invention has for its object to provide purification or recovery procedure whereby the foregoing difllculties are substantially lessened. Another object is to provide a method for recovering or purifying tocopherol wherein the tocopherol is prevented from being oxidized to an inactive form. Another object is to improve the able reactant to give nascent hydrogen. For instance, sodium reacts in the presence of alcohol to form sodium ethylate and nascent hydrogen. Sodium hydrosulphite (NaaSzOr) and'phosphite, stannous, chloride and like powerful reducing agents are satisfactory. Catalytic hydrogenation may be used.v The pressure may be atmospheric or higher such as 200- ats. Usual hydrogenation catalysts such as nickel, copper or nickel chromite, platinum, Dalladi etc., can be used. The temperature should be below 300 to prevent thermal decomposition.

The importantthing is to maintain the tocopherol oxidation products in the reduced form and prevent conversion to irreversible or diflicultly reversible forms. This does not necessarily mean that active reduction must take place during each second; of the purification or recovery treatment. It is perfectly feasible to apply the reduction intermittently or continuously during the stage of 'the'operations in which active oxiyields of tocopherol purification or recovery processes. Another object is to improve the state of the art. Other objects will become apparent from the following description and claims.

These and other objects are accomplished in accordance with our invention, which includes subjecting the tocopherol-containing material to a reducing treatment during the purification or recovery treatments. In this way the tocopherol is kept substantially entirely in a useful or active form during operations which would otherwise cause conversion to an inactive substance.

In the following description we have set forth several of the preferred embodiments of our invention, but it is to be understood that these are given for the purpose of illustration and not in limitation thereof.

Examples of suitable powerful reducing agents are zinc dust, in conjunction with acid or alkali.

7 Other metals than zinc which give rise to nascent hydrogen in the presenceof acids, such as acetic, hydrochloric, sulphuric, or alkalies, such as sodation is likely to take place.

Tocopherol is recovered from natural materials of the nature of vegetable oils by saponification and solvent extraction. Also tocopherol can be prepared by synthetic means. In Hickman application 321,913, filed March 2, 1940, there is described new source materials for tocopherol comprising sludges, scums, and other volatile by-products derived from vegetable and animal oils during carrier gas and like refining or deodorizing treatment thereof. The tocopherol is recovered from these by-products by various methods, such as acidification followed by high vacuum, unobstructed path distillation, saponiflcation, solvent extraction of the saponification mixture, followed by distillation of the non-saponifiable extract and like procedure. Our invention is applicable to the recovery or purification of tocopherol from these sources and to all methods of purification or recovery of tocopherol in which oxidation to the irreversible form can dium hydroxide can be used. Examples of such metals are aluminum, iron, and tin. Metallic take place.

Examrnn I Recovery of free tocopherol hydroquinone from crude deodorizer "clabber stock" (the volatile matter recovered from the steam employed in the deodorization 0'! a vegetable oil such. as hardened corn oil) Ten per cent zinc dust is stirred into the melted or partly melted crude clabber stock which contains about 2.3% tocopherol. After thoroughly incorporating, sufilcient alcoholic caustic soda of quires weapon! ture sets solid so that all but th surface layers .40 per cent strength is added and the mixture stirred and heated or allowed to warm spontaaeously to achieve complete saponiflcation which is accomplished in about one hour. A convenlent amount of alkali is 200 per cent of that gl'e- 4 y the fat, supposing thatiifi'le entire clabber stock is sly erlde. .An hoiinor more after the addition of alkali, the reduction oi tocopherol is complete and the sapcniiled mix- 2340,27: oxidised tocopherol. The concentrate is used as such or as raw material for further Emu: IV

Recovery ol-tooophaol Imm-hotaocll sludge from steam deodorization o! vedctcble a.:

Two samples of the sludge weighing 200 zrams each were One or the samples was reflned by intimately mixing with grams zinc dust and sumcient 10 per cent hydrochloric acid to completely react with the zinc dust. After completion oi the reaction the mixture was washed with water until acid is removed. The

sulphate and chilled to 0 C. or lower. Any sterols separating areflltered on. ,Ii quantitative removal of stemls is dejigred, remove the solvent and dissolve residuefi ethyl acetate, cool toI'O" C. and filter oi! the precipitated sterol. The solvent is now removed by. distillation under vacuum. vThe undistilled residue is a crude concentrate containing about 1'7 per cent free tocopherol substantially in the hydroquinone condition. The concentrate may be vacuum distilled or esteriiled. to produce further PrOducts oi tocopherol.

Exams!!! new or tocophercl from soi bean on "hotwell sludge? the volatile matter of a vegetable oil which is obtained dutiful steam deodorisation thereof and which condenses in the baro-.

metric sump) Y The hotwell sludge is mixed. with 2 per cent oi .itsweight of zinc dust by shading in a trough. The mixture is placed in a tank, preferably of or glass, and is steamed to melt the fat, preferably after a wait oi 15 minutes or more.

The water that separates may be drained away after which the mixture is agitated violently to .brins the zinc into suspension. Hydrochloric acid in slight excess oi that required to remove the zinc and any soaps is addedand the mixagitated at the boiling point with exclusion or The mixture is now allowed to separate. the aqueous acid layer is drawn on. and the supernatant fat is washed with hot water in the absence or air until free from mineral acid and metal soaps. The fat containing the reduced oxidation products of tocopherol is dried and filtered, after which the tocopherol may be distilled under high vacuum. An alternative to this procedure is to use powdered iron or aluminum for the reduction process.

EXAM? III Tre'atment'of a crude distillate of tocopherol A crude dlstillateoi' tooopherol obtained from the-high vacuum, unobstructed path distillation or a raw oil containing tocopherol, such as corn oil. as described in Hickman and Baxter application No. 201,018 died April 8, 1938, is taken into solution in ethyl alcohol and chilled to remove sterols. Sodium amalgam in double the amount required to neutralize the free fatty acids is add- .ed while the mixture is violently agitated until material is then dried with anhydrous NaaBOr and subjected to distillation in a high vacuum, unobstructed path still.

The other sample was treated with a like amount (200 cc.) 10 .per cent hydrochloric acid, washed. 'dried. and then distilled in the same manner. The course or this distillation is shown in Fig. 1 of the drawing wherein yield of tocopherol is plotted against temperature. It'is seen that the tocopherol exhibts two maxinia represented by the ordinary and oxidized forms. The recovery or tocopherol was 46.8 per cent.

j P18. 2 illustrates the results of the distillation on the first sample after reduction with zincdust and acid. 'All of the tocopherol is present in the copherol was. 70.4 per cent.

Amixtureofreducingagentsmaybeusedif desired. A partiwlarly satisfactory reduction is obtained by employins an active reducina agent which can be reversiblrondized and reduced, i. e., which can be caused to oscillate becillates between the stannous and stannic forms due to the oxidizing action of the quinone and the reducing action or the nascent hydrogen from the zincand acid.

Tocopherol is known to be a natural anticxidant. However, in the prior art it was believed that theantioxidant power was destroyed by any alkali treatment. While this is the usual case, we have found that toccpherol is not afiected by alkali while its oxidation products are and that, it the alkali treatment is carried out in combination with our invention. no loss 0! antioxidant power will take place. Another advancdoriser scum. lo

tage of the invention is that the reduction treatment removes materials which would otherwise deposit on the vaporizing surface ot'the unobstructed path still.

The advantages of the invention cannot be obtained merely by the utilisation of an inert gas, thus theuse oihydrogen asaninert casin the absence oi a catalyst will not ailect the reduction and my invention is not intended to in-' clude the mere usect inert cases includina: hy-

Reference is made to. Hlchnan application 321,913, filed March-2. 1N0. which relates to the preparation of tocopherol concentrates from de- Whatweclalmis: 1. In a process of puriiyin: 00111261010011:

tained in deodoriaer scumthejsteps which comprise subjecting the scum to the action oi a purifying and concentrating scent and to a powis slim scent which is capable of reduc asaaava ing at least part the oxidation products ot towpherol into a substance having substantially the same distillation temperature and vitamin E activity as the tocopheroi from which said oxidation products were derived, subjecting the reduced tocopherol preparation to high vacuum unobstructed path distillation and separating the tocopherol and its reduced oxidation products as a single fraction at a temperature of about- 2. In a process ior purifying tocopherol contained in a lighter-than-water scum removed from the vapors produced during the carrier gas treatment of a vegetable or animal oil-the step which comprises subie cting the scum-to the action of a purifying and concentrating agent and to a powerful reducing agent which is capable of converting oxidation products oi tocopherol into a substance having substantially the vitamin E activity and distillation temperature of the tocopherol from which said oxidation products were derived.

3. In a process 10: puriiyins tocopherol contained in a lighter-than-water scumcondensed from the steam utilized for thevacuum-steam' deodorization treatment of a vegetable or animal oilthe step wtwh comprises subjecting the scum to the action of a purifying and concentrating agent while in the presence of zinc dust tiable matter.

' KENNETH C. D. HICKMAN.

NOlliL' B. KUHRT. 

